High intensity illumination light table with attenuating and reflecting means coupled to rhomboid arms

ABSTRACT

A high intensity light table, for use with a stereomicroscope having movable rhomboid arms, has an illumination source and a reflector. The table also includes light diffusing members which are rotatably mounted thereto. The diffusing members have: (1) magnets affixed thereto which are responsive to movement of the rhomboid arms of the instrument; and (2) means therein for selectively passing a beam of high intensity illumination. An auxiliary reflector, which is rotatable about the source of illumination, may be employed to substantially increase the intensity of the beam of illumination.

CROSS-REFERENCE TO RELATED APPLICATION

This application is related to concurrently filed and copendingapplication Ser. No. 477,046 entitled "High Intensity Illustration LightTable" for inventor R. Martino.

DESCRIPTION OF THE PRIOR ART

The viewing of stereo photographs produced by aerial photography may bedone with stereomicroscope optical systems and high intensityillumination light tables such as illustrated in U.S. Pat. Nos.4,220,982 and 4,292,663. The stereomicroscope includes a pair ofrhomboid arms which are selectively positionable over the film beinganalyzed. The light table includes a parabolic reflector positionedabout a light source and which reflects light up through the filmsupport surface of the light table. The light provided sufficientlytransilluminates the film being viewed to enable detailed analysis. Theintensity of illumination required to enable such film analysis is, inmany instances, over 100,000 ft-lamberts. Although the illuminationprovided is directional and not scattered, it can be most irritating tothe operator when working close to the viewing stage. Consequently,viewing the intense light output many times will result in operator eyefatigue. Frequently, the operator must back away from the intense lightbeing emitted by the table. Accordingly, little productive work will beaccomplished during this period of time.

A further light table illumination device includes a condenser typeilluminator which is mounted below the glass surface of the light table.The condenser is connected via a fiber optic bundle which carries lightfrom a source remote. The condenser is moved by magnets which are fixedto the stereomicroscope rhomboid arms.

The illumination system of the present invention provides a solution tothe problem set forth above by providing diffusing discs which mimicrotation of the rhomboid arms of the instrument. The discs effectivelydiffuse unwanted illumination while permitting highly intensetransillumination of selected areas of the film being reviewed.

SUMMARY OF THE INVENTION

A high intensity light table for transilluminating film includes ahousing having a light transmitting surface. A light source is mountedin the housing below the light transmitting surface and includes areflector to reflect light from the source through the transmittingsurface. At least one light diffusing member is rotatably mounted to thehousing adjacent the light transmitting surface. In the preferredembodiment the diffusing member has an aperture therein which permitsundiffused light to pass therethrough. The rotatable diffusing memberand the rhomboid arm of the stereomicroscope used for viewing the filmare magnetically coupled such that rotation of the rhomboid arm thereofproduces a corresponding rotation of the diffusing member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the high intensity illumination lighttable of the present invention;

FIG. 2 is a partial section view in schematic taken alon line 2--2 ofFIG. 1; and

FIGS. 3-5 are enlarged partial section views similar to FIG. 2 showingalternative embodiments of the light table.

DETAILED DESCRIPTION OF THE INVENTION

A stereo viewing system 10 for viewing film taken by aerial photographyincludes a stereomicroscope 12, a film support and advance system 14 anda high intensity illumination light table 16.

The stereomicroscope 12 includes a structure 18 which has a pair ofeyepieces 20 and 22 rotatably mounted thereto to enable, as is wellknown in the art, the interpupillary distance to be varied. Structure 18further has rhomboid arms 24 and 26 which are also rotatably mountedthereto. The structure 18 is adjustably mounted to vertical support 28so as to be movable relative to the light table 16 thereby accomplishingfocusing of the stereomicroscope optical system (not shown).

The film support and advance system 14 includes a film supply sprocket30 and a film takeup sprocket 32 which are mounted to, respectively,support brackets 34 and 36. The brackets 34 and 36 are in turn slidablymounted to the light table 16 by any conventional well known manner (notshown). A pair of hold down members 38 and 40 are mounted to the lighttable 16 for retaining and positioning film 42 in the scanning stage 44.

The light table 16, as best seen in FIG. 2, includes a housing 46 havinga cover plate 48, constructed of clear glass. A pair of illuminatingsystems 52 are enclosed within the housing 46. Each illuminating system52 has a parabolic reflector 54 in which a quartz halogen tungsten lamp56 is fitted to electrically energizable socket 58. The lamp 56 ispreferably situated at the center of focus of the reflector 54. Power tolamp 56 may be controlled through control switch 58, as best seen inFIG. 1.

A pair of diffusing discs 60 and 62 are rotatably mounted via shoulderedbearings 64 and 66 which are received in suitable bores 68 and 70 incover plate 48, as illustrated in FIG. 2. The discs 60 and 62 are madeeither from a material which will pass, approximately, 4% of the lightfrom reflector 54, or are coated with a suitable material to obtain theproper percentage of light transmission. As parabolic reflectors 54 aresiamized together in the manner illustrated in the previously mentionedU.S. Pat. Nos. 4,220,982 and 4,292,663, the rotating diffusing discs 60and 62 must be mounted so that they overlap each other, as best seen inFIG. 2. This may be easily accomplished by using a bearing spacer toraise one diffusing disc a distance sufficient to allow the other discto fit partially below it.

Diffusing disc 60 has an aperture 72 and disc magnet 74 while diffusingdisc 62 has a similar aperture 76 and disc magnet 78. The disc magnets74 and 78 are, as illustrated in FIGS. 1 and 2, mounted in juxtapositionto the apertures 72 and 76. Rhomboid arms 24 and 26 have disc magnets 80and 82 which are complimentary to disc magnets 74 and 80. They areaffixed, respectively, to extensions 84 and 86. The magnetic attractionbetween the magnets on the rotating diffusing discs and thecomplimenting magnets on the rhomboid arms is such that rotation ofeither of the rhomboid arms causes a similar rotation in thecorresponding diffusing disc.

In operation, with the film 42 disposed across the scanning stage 44 andthe lamps 56 energized by switch 58, rhomboid arm 24, for instance,would be initially positioned over the aperture 72 of correspondingdiffusing disc 60. A portion of the light reflected by the parabolicreflector 54 would pass directly through disc aperture 72 and into theobjective lens of rhomboid arm 24 thereby illuminating that portion offilm positioned in the light path. The remainder of the light reflectedby the parabolic reflectors 54 would be substantially diffused by thediffusing discs 60 and 62 such that it is not discomforting to theoperator.

Once the area being viewed under rhomboid arm 24 has been properlydetermined, as described above, the other rhomboid arm 26 would berotated to find the corresponding exposed area of film to complete thestereo analysis. The magnetic attraction between the rhomboid arm andthe diffusing disc provides the same alignment between aperture andobjective as was described hereinabove for initial alignment of thefirst rhomboid arm. The operator may, therefore, look directly at thefilm 42 supported on the scanning stage 44 without being exposed to arather large area of very intense light, which may approach 200,000ft.-lamberts as set forth in the previously mentioned U.S. Pat. Nos.4,220,982 and 4,292,663. The only intense light to which the operator isexposed is directed through the small disc apertures 72 and 76.

In the embodiment shown in FIG. 3 a light table 110, similar to thelight table just described, includes a housing 112 which has a diffuserdisc 114 rotatably mounted by bearing assembly 116 to clear glasssupport 118. The diffuser disc 114 has an aperture 120 and a magnet 122.A source of illumination, such as lamp 124, is positioned in the housing112 in alignment with the axis of rotation 126 of the diffuser disc 114.A parabolic reflector 128 is fitted about the lamp 122. Additionally, aspherical reflector 130 is connected by linkage 132 to, for instance,diffuser disc 114 through bearing assembly 116 so as to be rotatableabout lamp 124 when diffuser disc 114 is rotated by magnetic attractionbetween magnet 122 and magnetic means on the rhomboid arm (not shown) aspreviously described.

Illumination from lamp 124 is reflected by parabolic reflector 128through glass support 118 where the greater portion is diffused by disc114. However, a portion of it does pass undiffused through disc aperture120. Auxilliary spherical reflector 130, which rotates with thediffusing disc 114 as described above, reflects a portion ofillumination from lamp 124 back through the disc aperture 120. Theilluminaton level through the disc aperture 120, and correspondingly,the film, can thereby be significantly increased.

In a further embodiment shown in FIG. 4, a light table 210 includes ahousing 212 which has a glass support 214. A diffuser disc 216 isrotatably mounted in bore 217 of glass support 214 via bearing assembly218. The diffuser disc 216 has an aperture 220 and a magnet 222. A pairof reflectors, 224 and 226, are connected to diffuser disc 216 onopposite sides of lamp 230 by linkage 228. Reflector 224 may be either aportion of a parabola or an ellipse, while reflector 226 is preferablyspherical.

The previously described magnetic attraction between the rhomboid arm(not shown) and magnet 222 causes the disc 216 to rotate when therhomboid arm is rotated. As the reflectors 224 and 226 are connected todiffuser disc 216 via linkage 228, they are also caused to rotate.Spherical reflector 226 reflects additional light from lamp 230 toreflector 224 and through diffuser disc aperture 220. The lightavailable to the stereomicroscope optics is thereby significantlyincreased. As there is no stationary reflecting surface, such as in theabove and other known devices, illumination not reflected by reflectors224 and 226 is harmlessly scattered about in the housing 212.

A still further embodiment is shown in FIG. 5 wherein a light table 310includes a housing 312 and a clear glass support 314. A diffuser disc316, rotatable about axis 318, is mounted in bore 317 of support 314 bybearing assembly 320. Like the previous embodiments, diffuser disc 316has an aperture 322 and a magnet 324. A crank arm 326 is connectedthrough aperture 327 of support 314 and bearing assembly 320 to diffuserdisc 316. The crank arm 326 has a support beam 328 which carries incantilever fashion lamp 330, spherical reflector 332, inclined mirror334 and condenser lens 336. Illumination from lamp 330 is reflected byinclined mirror 334 through condenser lens 336, support 314 and discaperture 322 to the stereomicroscope optics. Additional illuminationfrom lamp 330 is reflected back by spherical reflector 332 to mirror 334where it is directed through condenser lens 336 and, ultimately, to thestereomicroscope optics. A spot of high intensity illumination isthereby provided. It is evident that, as previously described in otherembodiments, rotation of the rhomboid arm causes rotation of thediffuser disc 316 which, in turn, rotates the crank arm 326 andassociated lamp, reflectors and lens. A stop mechanism (not shown) wouldbe employed to prevent wind-up of the electrical wires attached to thelamp 330.

In any of the above-described embodiments, it is evident that aplurality of fluorescent lamps (not shown) may be mounted in the housingto provide background illumination. Also, a diffusing cylinder may beplaced between the lamp and the reflector to eliminate unwanted imagingin the stereomicroscope.

The drawings and accompanying text have shown and described severalembodiments of my present invention. However, it should be readilyappreciated by those skilled in the art that various changes may be madethereto without departing either from the spirit or scope of theinvention.

We claim:
 1. A high intensity light table for transilluminating film forviewing with microscope optics supported by rhomboid arms, said lighttable comprising:(a) a housing having a light transmitting surface; (b)illuminator means positioned in said housing for providing highintensity illumination; (c) reflector means disposed in said housingrelative to said illuminator means such that when said illuminator meansis energized said high intensity illumination is transmitted to saidlight transmitting surface; (d) means rotatably mounted to said housingbetween said light transmitting surface and said illuminator for atleast partially attenuating said illumination, said attenuating meansincluding means therein for passing unattenuated at least a portion ofsaid high intensity light; (e) means secured to said attenuating meansresponsive to movement of said rhomboid arms, whereby rotation of saidrhomboid arms produces a corresponding rotation of said attenuatingmeans and said means for passing at least a portion of the beam of highintensity illumination; and (f) auxilliary reflector means coupled tosaid attenuating means to rotate corresponding therewith, saidauxilliary reflector means reflecting additional illumination given offby said illumination means through said means in said attenuating meansas said attenuating means is rotated.
 2. The high intensity light tableas set forth in claim 1, wherein said auxilliary reflector is spherical.3. The high intensity light table as set forth in claim 1, wherein saidattenuating means is a light diffusing disc.
 4. The high intensity lighttable as set forth in claim 1, wherein said disc is opaque.
 5. The highintensity light table as set forth in claim 1, wherein said reflectormeans is a partial parabolic section and said auxilliary sphericalreflector is connected thereto.
 6. The high intensity light table as setforth in claim 2, wherein said reflector means and said auxilliaryreflector means are disposed on opposite sides of said illumunatormeans.